Ki. Mcanally et al., COMPARISON OF CURRENT WAVE-FORMS FOR THE ELECTRICAL-STIMULATION OF RESIDUAL LOW-FREQUENCY HEARING, Acta oto-laryngologica, 117(6), 1997, pp. 831-835
Many cochlear prostheses employ charge-balanced biphasic current pulse
s. These pulses have little energy at low frequencies resulting in lim
ited stimulation of low frequency hearing by mechanical responses to t
he electrical stimulus. However, if electro-mechanical transduction wi
thin the cochlea is nonlinear, electrical stimulation with asymmetric,
charge-balanced current pulses may result in a mechanical response wi
th significantly more low frequency energy. We estimated the mechanica
l response at low frequencies to pulsatile electrical stimulation of t
he cochlea. The auditory nerve compound action potential evoked by low
frequency tones was forward-masked by a train of symmetric or asymmet
ric current pulses. Masking by asymmetric current pulses was not signi
ficantly different from masking by symmetric pulses matched for pulse
duration and charge. In conclusion, there appears to be no advantage t
o using asymmetric current pulses for the mechanical stimulation of re
sidual low frequency hearing by electrical stimulation of the cochlea.